<template>
   <view class="uni-numbox">
      <view @click="_calcValue('minus')" class="uni-numbox__minus uni-numbox-btns" :style="{background}">
         <text class="uni-numbox--text" :class="{ 'uni-numbox--disabled': inputValue <= min || disabled }"
            :style="{color}">-</text>
      </view>
      <input :disabled="disabled" @focus="_onFocus" @blur="_onBlur" class="uni-numbox__value" type="number"
         v-model="inputValue" :style="{background, color}" />
      <view @click="_calcValue('plus')" class="uni-numbox__plus uni-numbox-btns" :style="{background}">
         <text class="uni-numbox--text" :class="{ 'uni-numbox--disabled': inputValue >= max || disabled }"
            :style="{color}">+</text>
      </view>
   </view>
</template>
<script>
   /**
    * NumberBox 数字输入框
    * @description 带加减按钮的数字输入框
    * @tutorial https://ext.dcloud.net.cn/plugin?id=31
    * @property {Number} value 输入框当前值
    * @property {Number} min 最小值
    * @property {Number} max 最大值
    * @property {Number} step 每次点击改变的间隔大小
    * @property {String} background 背景色
    * @property {String} color 字体颜色（前景色）
    * @property {Boolean} disabled = [true|false] 是否为禁用状态
    * @event {Function} change 输入框值改变时触发的事件，参数为输入框当前的 value
    * @event {Function} focus 输入框聚焦时触发的事件，参数为 event 对象
    * @event {Function} blur 输入框失焦时触发的事件，参数为 event 对象
    */

   export default {
      name: "UniNumberBox",
      emits: ['change', 'input', 'update:modelValue', 'blur', 'focus'],
      props: {
         value: {
            type: [Number, String],
            default: 1
         },
         modelValue: {
            type: [Number, String],
            default: 1
         },
         min: {
            type: Number,
            default: 0
         },
         max: {
            type: Number,
            default: 100
         },
         step: {
            type: Number,
            default: 1
         },
         background: {
            type: String,
            default: '#f5f5f5'
         },
         color: {
            type: String,
            default: '#333'
         },
         disabled: {
            type: Boolean,
            default: false
         }
      },
      data() {
         return {
            inputValue: 0
         };
      },
      watch: {
         value(val) {
            this.inputValue = +val;
         },
         modelValue(val) {
            this.inputValue = +val;
         }
      },
      created() {
         if (this.value === 1) {
            this.inputValue = +this.modelValue;
         }
         if (this.modelValue === 1) {
            this.inputValue = +this.value;
         }
      },
      methods: {
         _calcValue(type) {
            if (this.disabled) {
               return;
            }
            const scale = this._getDecimalScale();
            let value = this.inputValue * scale;
            let step = this.step * scale;
            if (type === "minus") {
               value -= step;
               if (value < (this.min * scale)) {
                  return;
               }
               if (value > (this.max * scale)) {
                  value = this.max * scale
               }
               // 监听减的事件
               this.$emit("minus", value)
            }
            if (type === "plus") {
               value += step;
               if (value > (this.max * scale)) {
                  return;
               }
               if (value < (this.min * scale)) {
                  value = this.min * scale
               }
               // 监听加的事件
               this.$emit("plus", value)
            }

            this.inputValue = (value / scale).toFixed(String(scale).length - 1);
            this.$emit("change", +this.inputValue);
            // TODO vue2 兼容
            this.$emit("input", +this.inputValue);
            // TODO vue3 兼容
            this.$emit("update:modelValue", +this.inputValue);
         },
         _getDecimalScale() {

            let scale = 1;
            // 浮点型
            if (~~this.step !== this.step) {
               scale = Math.pow(10, String(this.step).split(".")[1].length);
            }
            return scale;
         },
         _onBlur(event) {
            this.$emit('blur', event)
            let value = event.detail.value;
            if (!value) {
               // this.inputValue = 0;
               return;
            }
            value = +value;
            if (value > this.max) {
               value = this.max;
            } else if (value < this.min) {
               value = this.min;
            }
            const scale = this._getDecimalScale();
            this.inputValue = value.toFixed(String(scale).length - 1);
            this.$emit("change", +this.inputValue);
            this.$emit("input", +this.inputValue);
         },
         _onFocus(event) {
            this.$emit('focus', event)
         }
      }
   };
</script>
<style lang="scss" scoped>
   $box-height: 26px;
   $bg: #f5f5f5;
   $br: 2px;
   $color: #333;

   .uni-numbox {
      /* #ifndef APP-NVUE */
      display: flex;
      /* #endif */
      flex-direction: row;
   }

   .uni-numbox-btns {
      /* #ifndef APP-NVUE */
      display: flex;
      /* #endif */
      flex-direction: row;
      align-items: center;
      justify-content: center;
      padding: 0 8px;
      background-color: $bg;
      /* #ifdef H5 */
      cursor: pointer;
      /* #endif */
   }

   .uni-numbox__value {
      margin: 0 2px;
      background-color: $bg;
      width: 40px;
      height: $box-height;
      text-align: center;
      font-size: 14px;
      border-left-width: 0;
      border-right-width: 0;
      color: $color;
   }

   .uni-numbox__minus {
      border-top-left-radius: $br;
      border-bottom-left-radius: $br;
   }

   .uni-numbox__plus {
      border-top-right-radius: $br;
      border-bottom-right-radius: $br;
   }

   .uni-numbox--text {
      // fix nvue
      line-height: 20px;

      font-size: 20px;
      font-weight: 300;
      color: $color;
   }

   .uni-numbox .uni-numbox--disabled {
      color: #c0c0c0 !important;
      /* #ifdef H5 */
      cursor: not-allowed;
      /* #endif */
   }
</style>
